Means for providing plural electrical intercommunication between relatively moving terminals

ABSTRACT

A plural conductor cable and cable-carrying apparatus for interconnecting a control console mounted to a movable platform and a relatively stationary control means. The cable-carrying apparatus is comprised of a spring-biased reel means which causes a single unbroken length of ribbonlike cable to be wound back on itself about the drum of the reel means as the tension applied to the ends thereof is relaxed so that no slack is allowed to develop in the cable. On the other hand, the cable is played out in two directions upon application to the cable of a tension exceeding the spring return force of the reel means.

United States Patent Lynn D. Crawford San Jose, Call. 819,804

Apr. 28, 1969 Aug. 3, 1971 Mobility Systems, Inc. Santa Clara, Calif.-

[72] Inventor [21 Appl, No. [22]. Filed [45 Patented [73] Assignee [54] MEANS FOR PROVIDING PLURAL ELECTRICAL INTERCOMMUNICATION BETWEEN RELATIVELY MOVING TERMINALS SChirngADrawingl-h.

[5211.].8." 182/148 [511 Incl. E04g1/l8 [501FieldoISearch 182/148,

Primary ExaminerReinaldo P. Machado Attorney-Lowhurst & Hamrick ABSTRACT: A plural conductor cable and cable-carrying apparatus for interconnecting a control console mounted to a movable platform and a relatively stationary control means. The cable-carrying apparatus is comprised of a spring-biased reel means which causes a single unbroken length of ribbonlike cable to be wound back on itself about the drum of the reel means as the tension applied to the ends thereof is relaxed so that no slack is allowed to develop in the cable. On the other hand, the cable is played out in two directions upon application to the cable of a tension exceeding the spring return force of the reel means.

CONTROL MEANS Patented Aug. 3, 1971 3,596,736

2 Sheets-Sheet 1 CONTROL MEANS INVENTOR LYNN D. CRAWFORD BY K ATTORNEY MEANS FOR PROVIDING PLURAL ELECTRICAL INTERCOMMUNICATION BETWEEN RELATIV ELY MOVING TERMINALS BACKGROUND on THE INVENTION One of the primary problems associated with control systems in which the operator moves relative to the motive power source involves the manner in which the operator's control signals are transmitted to the driving power source. Perhaps the most basic manner in which control impulses are transmitted to a driving unit is by means of one or more cables connecting the control console with the power source. When there is relative movement between the objects attached to the opposite ends of the cable, there arises a problem as to what to do with the loose cable when the objects are closer together than the length of the connecting medium. One alternative is to let the cable dangle, but in many applications this is entirely unsuitable and means must be provided for accommodating the unused length.

In elevating apparatus such as is incorporated in some types of warehousing vehicles wherein the platform upon which the operator stands is movable relative to the motive power source, it is highly desirable that means be provided for taking up any slack in the connecting cable joining the two. In the more sophisticated system wherein a plurality of connecting paths between the control platform and the power source are involved and the data transmitted between the two remote locations is very susceptible to distortion, as in digital communication systems and the like, the manner in which the connecting cable is handled becomes quite important.

In the past, plural wire cables have been used in such devices and in order to handle the connecting cable, a springloaded drum means has been provided as a cable takeup means. However, in order to couple the innermost wound end of the cable out of the takeup reel, wiping contact means or the'like, must be provided. In modern elevating equipment, such a system is unsuitable because of the practical limitation as to the number of lead contactors which can be provided on the drum and secondly, because of the noise introduced into the system by the contact wipers.

OBJECTS OF THE PRESENT INVENTION It is therefore a primary object of the present invention to provide a novel mechanism for communicatively joining a control station with a controllable power means in a manner which permits the use of a far greater number of electrical interconnect channels than was heretofore possible.

Another object of the present invention is to provide a novel communicative interconnect mechanism for use between a relatively moving control means and the controlled prime mover which does not require the use of wiping contacts and wherein a single length of connecting cable can be utilized and maintained taut between the relatively movable interconnected communicative entities.

Still another object of the present invention is to provide a novel apparatus for electrically interconnecting the load platfonnmounted control console of a warehousing vehicle with the control responsive driving apparatus thereof.

SUMMARY OF THE PRESENT INVENTION The present invention relates generally to electrical cable interconnect apparatus and, more particularly, to a novel communicative interconnecting cable handling apparatus for use in elevating devices such as warehousing vehicles and the like.

i In accordance with the present invention, a multiconductor ribbon cable and retractor apparatus is provided for electrically interconnecting a warehousing vehicle control console mounted on a movable loading platform with the prime mover system mounted on a nonelevated portion of the vehicle. In

order to accommodate the changing length requirements as the load platform is elevated relative to the nonelevated structure, a spring-loaded ribbon cable, reel takeup assembly is provided. The takeup assembly allows the use of a single length of ribbon cable and thus does not require the use of wiping mechanical contactors. Since no contactors are required, low level electrical signals may be conducted through the wires of the cable without concern for contactor interference.

Other advantages of the present invention will become apparent to those skilled in the art after having read the following detailed disclosure of a preferred embodiment which makes reference to the several figures of the drawing.

IN THE DRAWING FIG. 1 illustrates a telescoping platform elevating mechanism including a cable intercommunication unit in accordance with the present invention.

FIG. 2 is a partially broken away perspective illustrating in more detail the cable-retracting reel mechanism of the present invention.

FIG. 3 is a partially broken away side elevation of the reel assembly and ribbon end connecting .means in accordance with the present invention.

FIG. 4 is a cross section taken through the reel assembly of FIG. 3 along the lines 4-4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT jack means 20 coupled at the end 22 to the fixed mast and at I the top end 24 to a crossmember 26 of the telescopic mast l8 Telescopically mounted to the mast 18 is the support and guide structure 28 of the load platform 12. In order that the full advantage of the telescoping lift mechanism be obtained so that the platform 12 can be lifted from a base elevation 30 to an elevation as indicated which is twice the height h to which the telescopic mast 18 may be elevated, the platform 12 is connected to the fixed mast 14 by a pair of cables 32 which pass over pulleys 34 attached to the top of the telescopic mast 18. This type of lifting structure is, of course, well known in the prior art.

Where such a structure is utilized as a lift mechanism for modern elevating structures, such as in warehousing vehicles and the like having a control console 36 carried on the platform 12, it is necessary that a communication means be provided for coupling the control console 36 to a vehicle control means 38 which is not carried by the lift platform 12. In modern elevating devices, digital control transmission techniques utilizing low level electrical signals to transmit a plurality of indicia have been found suitable for such applications.

In some modern complex systems, it may be necessary to provide as many as or more separate channels of communication between the load platform and the control means 38. Whereas, the prior art apparatus utilizing a drum-type cable retracting means with wiping mechanical contactors, a practical upper limit of the number of electrical conductors was perhaps a dozen or less, the use of modern ribbon-cabling apparatus will permit perhaps ten times that many data-handling channels to be provided between the control console 36 and the control means 38.

In order to accommodate the variable length requirements of the ribbon cable 40, a retractable reel assembly 42 is prosingle ribbon cable 40 folded back on itself with the folded portion wound about the reel 42 such that when the platform 12 is raised the two ends of the folded wound portion will be dispensed from the drum 44 of the reel 42 in opposing directions. Upon lowering of the platform 12, the cable 40 will be rewound back onto the reel assembly 42 in the manner illustrated in the drawing. it will be noted that a spring means 46 is provided for biasing the drum 44 so as to cause it to rotate in the counterclockwise takeup direction.

Referring now specifically to FIGS. 3 and 4, it will be noted that the reel assembly 42 is comprised of two circular end plates 48 which are spaced apart by the cylindrical drum 44 and are joined together by four connectors 52 into which suitable screw means 54, or the like, are threadably received. One of the connectors 52 also serves as a means to which one end of the spring 46 may attached. The other end of the spring 46 is secured to the axle pin 56 of the reel assembly which is mounted to the crossmember 26 of the telescopic mast section 18.

The manner in which the ribbon 40 is wound about the drum 44 can be understood by imaging the two ends 40 and 40' of a suitable length of cable as being folded together to form a loop 60 at the midpoint of the cable. The loop 60 is then inserted over a pin 62 which is positioned adjacent a slit 64 in the drum 50. The folded together cable is then wound about the drum 50 in the clockwise direction until enough of the ribbon is contained on the drum to allow the lifting apparatus to be extended to its full length. The end 40 is then carried upwardly to a'clamp means 66 wherein it is affixed to a portion 13 of the lift structure 12. in the illustrated embodiment, the clamp means 66 is of a type which pennits the ribbon to be divided so that a selected number of the cables 40 can be separated into a subnbbon 68 for extension to the left i then extended downwardly where it is clamped to a springloaded clamp member 72 so that the end 73 thereof may be extended to the control means 38 as illustrated in FIG. 1 of the drawing. The clamp member 72 is movable in the vertical direction parallel to the portion 40' of the ribbon, but is biased downwardly by a spring means 74. The spring-biased clamp 72 is required in order to account for the difierence in unwound length of the cable portions 40 and 40 due to the difference in winding diameter caused by their own thickness.

in operation, with the platform 12 in the lowest position 30 as indicated in FIG. 1, substantially all of the ribbon 40 is wound about the reel assembly 42. However, as the hydraulic cylinder is actuated to drive the platform 12 upwardly, the telescopic mast 18 will be driven one-halfas far in the upward direction as the platform 12 has been driven at any particular time. Since the reel 42 is carried by the crossmember 36 of the telescopic mast 18, it likewise, will be displaced one-half the distance that the platform 12 is displaced.

As the reel 42 is displaced upwardly, the tension on the cables will cause it to rotate in the clockwise direction and dispense substantially equal lengths of cable 40 and 40'. Because substantially equal amounts of cables are being simultaneously dispensed, it can be seen that one-half of the required cable extension will be dispensed upwardly and onehalf downwardly. Likewise, as the platform 12 is lowered the reel 42 will be caused to rotate in the counterclockwise direction by the spring means 46 so as to take up substantially equal lengths of cable 40 and 40' so that the interconnecting medium is maintained taut between the clamps 66 and 72 as the sition of the platform 12 is changed.

us, it can readily be seen that in accordancewith the present invention a communicative data interconnect means had been provided for use between a displaceable control panel 36 and a relatively stationary control means 38 which requires no mechanical wiping contactors, which requires no twisting of the interconnecting cable, and which permits the use of substantially more individual conductors than was possible using prior art devices.

After having read the above disclosure, many alterations and modifications of the invention will be apparent to those of skill in the art. it is therefore to be understood that this description is of a preferred embodiment disclosed for purposes of illustration only and is in no manner intended to be limiting in any way. Accordingly, it is intended that the appended claims be interpreted as covering all modifications which fall within the true spirit and scope of the invention.

What I claim is:

1. In a lift apparatus including a base, a mast disposed to move vertically relative to said base, a load platform disposed to move vertically relative to said mast, and coupling means communicatively coupling said load platform and said base, an improved coupling means, comprising:

a reel means including, a cylindrical drum rotatably mounted to said mast, spring means biasing said drum in a first rotational direction about its axis, and securing means; and

a ribbon cable including a plurality of electrical conductors disposed therein in planar parallel disposition, said ribbon cable having one end affixed to said load platform, the other end affixed to said base, and its midsection folded to form a folded portion, said folded portion being secured to said drum by said securing means and being wrapped around said drum in a second rotational direction opposite to said first rotational direction, whereby said spring mans maintains said cable taut as said load platform is raised and lowered.

2. in a lift apparatus as recited in claim 1 and further comprising a resilient fastening means resiliently fastening one of said cable ends to the lift apparatus to compensate for differentials in the lengths of the sections of cable making up said folded portion as said folded portion is wound and unwound upon said drum.

3. in a lift apparatus as recited in claim 1 wherein said drum includes a slit for receiving the fold of said folded portion, and said securing means includes a pin affixed to and disposed within said drum for mating engagement with said fold. 

1. In a lift apparatus including a base, a mast disposed to move vertically relative to said base, a load platform disposed to move vertically relative to said mast, and coupling means communicatively coupling said load platform and said base, an improved coupling means, comprising: a reel means including, a cylindrical drum rotatably mounted to said mast, spring means biasing said drum in a first rotational direction about its axis, and securing means; and a ribbon cable including a plurality of electrical conductors disposed therein in planar parallel disposition, said ribbon cable having one end affixed to said load platform, the other end affixed to said base, and its midsection folded to form a folded portion, said folded portion being secured to said drum by said securing means and being wrapped around said drum in a second rotational direction opposite to said first rotational direction, whereby said spring mans maintains said cable taut as said load platform is raised and lowered.
 2. In a lift apparatus as recited in claim 1 and further comprising a resilient fastening means resiliently fastening one of said cable ends to the lift apparatus to compensate for differentials in the lengths of the sections of cable making up said folded portion as said folded portion is wound and unwound upon said drum.
 3. In a lift apparatus as recited in claim 1 wherein said drum includes a slit for receiving the fold of said folded portion, and said securing means includes a pin affixed to and disposed within said drum for mating engagement with said fold. 